But most people missed a subtle detail on the invitation that reveals she was once married, according to royal observers.

The invitation read: "His Royal Highness The Prince of Wales K.G., K.T. requests the pleasure of the company of (name) at the marriage of His Royal Highness Prince Henry of Wales with Ms. Meghan Markle at St George's Chapel, Windsor Castle on Saturday 19th May 2018 at 12 noon followed by a reception at Windsor Castle."

Instead of referring to Markle as "Miss," it said "Ms."

This differed to that of the royal wedding for the Duke and Duchess of Cambridge in 2011 in which Middleton was referred to as "Miss Catherine Middleton."

"Ms" is the correct way to address a divorced woman according to proper etiquette, says royal commentator and manners coach William Hanson, who told the Mail Online that it is first time the royal household has acknowledged it.

"The royal household, in particular the Queen, has never before acknowledged the honourific Ms — regardless of whether it was being used to signify a divorced woman or one who did not feel her marital status was of importance.

"It was first used in connection to Meghan in the November engagement announcement and since then has been used throughout the royal household's communications, on press releases, invitations, and social media," he went on.

"It is another subtle sign that the royal household is moving with the times."